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Modulated supersonic molecular beam （SMB） injection is introduced to study transport features of non-local transport phenomenon on HL-2A. Repetitive non-local effect induced by modulated SMBI allows Fourier trans-formation of the temperature perturbation, yielding detailed investigation of the pulse propagation. Fourier analysis provides evidence for existence of internal transport barriers. Meanwhile, experimental progress of nonlocal effect was made in the HL-2A Tokamak in 200Z The core electron temperature Te rise increases from 18% to more than 40% and the duration of the Te rise could be prolonged by changing the conditions of SMB injection. 相似文献
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在HL-2A 装置上优化和发展了偏滤器靶板上的红外测温系统,并利用该系统分析了高约束模放电期间边缘局域模的热沉积分布特性。在高约束模式放电期间,超声分子束注入使边缘局域模所引起的偏滤器靶板上瞬间热通量峰值下降了~60%,并伴随着边缘局域模爆发频率增加了2~3 倍,而等离子体储能仅下降了~8%。分析结果表明,大幅度的丝状结构在超声分子束注入之后得到了有效抑制,沉积到偏滤器靶板上的瞬间热通量峰值也随之下降。此外,在超声分子束注入之后偏滤器室内的热辐射损失大幅度增加,从而耗散了热输运所携带的部分能量,进一步分散了沉积到偏滤器靶板上的能量,有效地保护了偏滤器靶板。 相似文献
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The electron density profile peaking and the impurity accumulationin the HL-2A tokamak plasma are observed when three kinds offuelling methods are separately used at different fuelling particlelocations. The density profile becomes more peaked when theline-averaged electron density approaches the Greenwald density limitnG and, consequently, impurity accumulation is oftenobserved. A linear increase regime in the density range ne<0.6nG and a saturation regime in ne > 0.6nGare obtained. There is no significant difference in achieved densitypeaking factor fne between the supersonic molecular beaminjection (SMBI) and gas puffing into the plasma main chamber.However, the achieved fne is relatively low, in particular,in the case of density below 0.7nG, when the workinggas is puffed into the divertor chamber. A discharge with adensity as high as 1.2nG, i.e. ne = 1.2nG,can be achieved by SMBI just after siliconization as a wallconditioning. The metallic impurities, such as iron and chromium,also increase remarkably when the impurity accumulation happens. Themechanism behind the density peaking and impurity accumulation isstudied by investigating both the density peaking factor versus theeffective collisionality and the radiation peaking versus densitypeaking. 相似文献
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The identification of the magnetic island structure in the HL-2A tokamak is presented. First, the perturbation current as a source for the perturbation flux can be determined by using Mirnov probe measurements. By superposing the perturbation flux and the equilibrium flux reconnected by equilibrium fitting, the structure and the width of the magnetic islands can be estimated. The method has been used in the HL-2A experiments. 相似文献
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HL-2A tokamak is the first tokamak with divertors in China. Theplasma boundary and the position of the striking point on the targetplates of the HL-2A closed divertor were simulated by the currentfilament code and they were in agreement with the diagnostic resultsin the divertor. Supersonic molecular beam injection (SMBI) systemwas first installed and tested on the HL-2A tokamak in 2004. In thepresent experiment low pressure SMBI fuelling on the HL-2A closeddivertor was carried out. The experimental results indicate that thedivertor was operated in the `linear regime' and during the period ofSMB pulse injection into the HL-2A plasma the power density convectedat the target plate surfaces was 0.4 times of that before or afterthe beam injection. It is a useful fuelling method for decreasing theheat load on the neutralizer plates of the divertor. 相似文献
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报道了HL-2A装置最新的实验结果,讨论并研究了超声分子束的注入位置对分子束在等离子体中的消融和穿透的影响,其中包括电离后的分子束粒子在磁场梯度作用和 E × B 漂移下的加速或减速及由此形成的冷通道效应.研究结果表明,磁场梯度和 E × B 漂移对于超声分子束的加料效果、消融和穿透有着重要的作用.强场侧注入可使电离后的电子和离子更深地进入等离子体芯部.这些研究对于更好地理解超声分子束与等离子体的相互作用和优化设计加料系统有一定作用. 相似文献
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分子束注入（MBI）是一种新的托卡马克加料方法，其已成功地在HL-1M装置上开发，并应用于HL-2A装置。分子束注入在改善等离子体约束性能方面具有很多优点，如形成密度峰化，提高能量约束时间等。在过去的分子束注入实验中，发现了一些很有物理意义的现象。但是到目前为止，分子束注入的机制还不是很清楚。 相似文献